There was one problem - on linux, if you use sbcl, and drop into sbcl debugger, there was no method to enter anything, so you basically stuck. Problem was what sbcl debugger talks with the terminal directly, bypassing stdio. So I had to patch the python script to use Pty module.Sent the patch to the author, hope he'll fix the next version.

dmgenp wrote:another hint: when working with threads under sbcl, if debugger is invoked within non-main thread, use (sb-thread:release-foreground) to switch to that thread to choose the restart.

I didn't know that you could use sb-thread:release-foreground to switch threads. Tips like this make this forum helpful. Thanks for pointing out something that is helpful to us all. i will try this next time I am in this situation.